The present invention relates to an ink jet system printer including an electro-mechanical transducer secured to a nozzle.
It is required that an ink droplet formation is stabilized in order to ensure a stable operation and an accurate printing. To stabilize the ink droplet formation, an ink jet system printer is proposed, which includes an ink liquid warmer for maintaining an ink liquid temperature at a constant value. However, this type of ink jet system printer can not respond to a rapid change in the ambience temperature and requires a long time period of start-up driving before initiating an actual printing operation. Moreover, it is not warranted that the ink liquid characteristics are fixed even when the ink liquid temperature is held at the constant value.
Accordingly, an object of the present invention is to provide an ink jet system printer for ensuring a stable operation and an accurate printing.
Another object of the present invention is to provide a control system for stabilizing the ink droplet formation in an ink jet system printer.
Still another object of the present invention is to provide a novel ink droplet issuance device in an ink jet system printer.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a control system is provided for varying a voltage level of an excitation signal applied to an electro-mechanical transducer which is attached to a nozzle for emitting ink droplets. A detection system is provided for detecting a charge condition of ink droplets, the detection result being indicative of the droplet formation condition. The voltage level of the excitation signal is automatically controlled in response to the detection result derived from the detection system, thereby maintaining the droplet formation condition in a preferred range without regard to the temperature variations.